Liquid conveying apparatus



July 28, 1959 R. A. v oN LINDE ETAL. 2,896,701

LIQUID CONVEYING APPARATUS Filed Sept. 30, 1955 LIQUID CONVEYilNG APPARATUS Robert A. Von Linde, Planegg, near Munich, Walter Baier, Stockdorf, near Munich, and Alfons Hartmann, Munchen-Pasing, Germany, assignorsto Wilhelm Baier, KG., Stockdorf, near Munich, Germany Application September 30, 1955, Serial No. 537,834

Claims priority, application Germany October 7, 1954 7 Claims. (Cl. 158-40) This invention relates to a device for the conveying of liquids and more particularly to the sup-ply of burners with liquid fuel and has special reference to `an improvement of the device disclosed in the copending patent application Ser. No. 443,128, tiled July 13, 1954, now abandoned, in which centain of the ,applicants of this application are parties to said application.

The device described in the said copending patent application comprises an ascending -tube or riser -provided lin the fuel duct leading from the supply tank to the burner or other consumer, `so .as to ascend `to a level above the level in lthe supply tank, and being exposed yto the action of heat ,at least in its part below the supply tank level, to such Aan eX-tent that the difference between the two levels `is overeome.

In order to meter `the amount of liquid supplied lto the consumer, a receptacle is inserted between ,the eonsumer and the liquid supply ,of the device `according tto .said patent application. The liquid is ,conveyed through the heated ascending pipe vinto the receptacle and from the receptacle it is fed, :through `a metering device, to the OnSllmer- `Arly liquid `possi-bly .conveyed in excess ows from the kreceptacle ythrough a (return pipe back yinto the supply tank.

We have now found .by further researches and QSS that in this arrangement the returning heated liquid causes an undesirable and possibly detrimental heating :of the liquid supply in the supply tank. Moreover it has been found that lthe discharge .of the liquid :through the nozzle in the :receptacle ofwing to the change of :Viscosity in ease of variation of the temperature does not remain constant, so that the supply may become irregular. This may have very detrimental elfeets., for instance, where fuel `.is supplied to a burner. 4

lt is an object of the present invention .to avoid :these drawbacks.

Another object of the invention is ,to provide an `arrangement permitting the use of `cheap fuel and yet preventing obstructions of the control nozzle.

A still further `objectof :the invention is to provide an an'angement ensuring .a uniform feed of fuel `and preventing the formation `of soot in `the burner, even `in case Aof readjustment of the fuel supply.

A still further object of the invention is `to prevent the `deposition of residues of .oil in .the thermal .conveying system.

With these objects in View according to thepresent invention the thermal conveying system is thermally separated from the regulating system of the arrangement. This thermal separation between the `regulating system and the conveying system is effected for instance by connecting the means for regulation and metering of `the fuel discharge directly tothe supply tank, yin `such a Lway that the liquid passes `fto the thermal conveying system in cold state, -while the conveying to the level above Vthe supply tank level and the subsequent supply of the conate ICC

sumer is effected after the regulation, by the thermal conveying system.

This arrangement not only 4avoids the above mentioned drawbacks but also permits the use of a larger control nozzle, because for instance in case of the conveying of oil this oil has a higher viscosity in `cold condition as it enters into the control system. Such a larger control nozzle however is much less exposed to the danger of obstructions and thus permits the use off a fuel which is filtered less `thoroughly and accordingly is cheaper.

According to a further yfeature of the invention a bypass circuit is inserted in the thermal conveying system. ln this way the formation of bubbles occurring in the thermal conveying system `when readjusting the fuel supply, owing to the increase of temperature of the fuel now passing through the same heating zone in a lower quantity, with the result `of an intermittent feed of fuel to the burner and the formation of soot in the burner can be completely avoided.

Another advantage of this bypass or auxiliary circuit consists in the fact that the danger of deposits of residues of oil in the thermal feed system is entirely avoided. Hitherto, by the possible overheating in the conveying system, a certain polymerization of oil occurred, -resulting in depositions in the pipe system. This is because the liquid llowing partly in the circuit not only is heated less, but also its speed of circulation is accelerated in case of an increased supply of heat, so that depositions possibly forming cannot -settle but are washed away. Moreover the liquid is in motion as long as any heat is transmitted from the burner to the heated ascending tube. In some instances, especially where the fuel is highly volatile, lthe riser may be heated to such a temperature that the vfuel in the riser is at least partly evaporated.

Other and further objects, features and advantages of the invention will be pointed out hereinafter and appear in the appended claims forming part of the application.

In the accompanying Adrawings a now preferred embodiment ofthe invention is shown by way' of illustration and not `by -way of limitation.

In the drawing, which shows a diagrammatic lsectional View of a fuel feed system having `the invention applied thereto, the fuel tank 11 consists of an upper part 12 and a lower part 13 in which the constant fuel level "s is maintained, which is determined :by the lower edge of the level tube 14 'whose upper end is closed by a cover 39 permitting the passage of atmospheric air into the tube 14 and acting to hold down a rod 40 for opening the valve passage between a `ball 41 and its seat 42 against action of a compression spring 43 which is adjustable by a screw 44 threadably engaged in a tubular extension 45 of the tank 11. A tube 46 extends Afrom a Ilevel below level ",s into a dome `47 in such a way that its upper edge is above the upper edge of the mouth of tube lf-i. The ring 4S serves to guide the rod 40. Provided in the portion 13 of the tank which communicates with the atmosphere through a tube 15, there is moreover a small supply vessel i6 for the reception of the supply of fuel for heating `up the burner and starting the `thermal feed which will be hereinafter described.

The fuel ows from the supply vessel through a con necting duct 17 to a'regulating vessel 1S consisting of two chambers 19 and Z0. From the chamber 19 which is closed by a screw plug 49 the fuel passes through a channel 21 into the chamber 20 which is provided with an adjusting nozzle 22 having a `bore 23 which can be closed by a control member 24 which is urged into its closed position by action of a compression spring 25.

The control member 24 `can be opened and closed or Aadjusted to a desired cross section by readjusting a rod 26 threadably engaged in a sleeve member 50 screwed into a threaded bore of the casing 18. In accordance with the size of the open cross section left between the bore 22 and the control body 24, more or less fuel passes into' a third chamber 27 from which the fuel flows through a pipe 2S to a heated ascending pipe 29 which 4is thermally connected with a burner 30 so as to permit the conduction of heat from the burner to the ascending pipe.

The ascending pipe 29 is connected to a return pipe 3l reaching a level above the level s and then into a descending pipe 32 from which it is discharged into the burner 3i) through a pipe 33. The top point of pipe 31 is vented by a vent pipe 31'.

A bypass pipe 34 is connected in parallel to the ascending pipe 29 at a point below level .s. Pipes 35, 36, 37 and a three-way-valve 33 serve for supplying the burner with the amount of fuel provided in the vessel 16 for ignition, depending o-n the position of the valve 38 as will 'be hereinafter described.

ln case of a rotation of the valve 38 through 180 from the position as shown the supply of fuel in pipe 17 communicates directly with the burner, bypassing the regulating system 18 and the thermal `feed systems 29, 31, 32.

The heated portion of the riser 29 preferably is arranged at a relatively low level which may be lower than that shown in the drawing, as indicated by the broken-off portions.

The operation of the arrangement is as follows:

On removal of the cover 39 the fuel is filled into the filling tube 14 extending at its upper end in the form ofva funnel; simultaneously the rod 4t) is relieved and the ball 41 closes the valve opening 42 so as to prevent the fuel from flowing into the chamber 13. The air in the space above the rising fuel level in the chamber 12 is permitted to escape through the pipe 46 and then through the vent pipe 15. The valve 41, 42 is then opened by closing the cover 39, whereby the chamber 13 is iilled up to the level "s.

In the position of the three-way valve 33 as shown the chamber 16 is filled up to the level "s. Now the burner can be ignited by turning the three-way valve 38 through 90 in an anti-clockwise direction, so that the contents of the chamber 16 is emptied through pipes 35, 37 into the cup Sti of the burner. The flame 3h now will heat the tube Z9 which has been filled with fuel through pipes 27, 23 and cause the `fuel to rise above the level "s, by thermal effects, up to the level 31, with the result that it is fed to the burner Sil through pipesr32, 33 thus maintaining a continuous combustion.

The fuel passing through 117, 19, 21, 22, 27 is metered by the regulating system 18 as hereinbefore described, whereby the combustion can be regulated very accurately. It will be seen that the cross section of passage of the feed system is larger than the cross section of passage of the control system.

In case of a reduction of the fuel supply by readjustment of the control member 23 and in case of au excess of heat still present in the burner the fuel is partly circulated through the bypass pipe 34, the speed of this circulation depending on the residual heat of the burner.

incase of a complete stoppage of the fuel supply the thermal feed system does not come to a standstill simultaneously, whereby normally the fuel in the ascending pipe 29 would be heated excessively and thus the formation of bubbles and an irregular feed of fuel 'would result. However, owing to the provision of the bypass 34, the fuel in this case circulates through said bypass pipe 34 until it finally comes. to a standstill as the burner cools down. Thus any heating of the fuel is avoided, the formation of Ibubbles is prevented and polymerization of the oil cannot occur, so that depositions are largely eliminated or washed away from the walls of 4 the pipes through the continuous circulating fuel. direction of iiow is indicated by the arrows.

It will be understood that. if the burner flame would be extinguished for some reason or other, the fuel feed will be stopped automatically as the riser 29 cools down. Owing to the vent pipe 31', a Siphon effect cannot occur.

While the invention has lbeen described in detail with respect to a now preferred example and embodiments of the invention it will be understood by those skilled in the art after understanding the invention that various changes and modifications may be made without departing from the spirit and scope of the invention and it is intended, therefore, to cover all such changes and modifications in the appended claims.

We claim:

l. In a liquid consuming system, a consumer, a fuel tank at a higher level than said consumer, means to maintain a fuel level below a maximum in said tank, an outlet in the lower part of said fuel tank, fuel conduit means between ysaid outlet to said consumer, a thermal feed system including a riser forming part of said fuel conduit means, said riser having an upper end at a level above said maximum fuel level in said tank, a portion of said fuel conduit means leading from said upper and downward to said consumer, means for heating at least a portion of said riser at a level lower than the lowest point of said outlet for lifting the fuel in said riser to at least said upper end by thermal action from where the fuel flows through said descending fuel conduit portion to said consumer, a conduit by-passing said riser by connecting the latter at a point somewhat lower than said upper end with the lower end of said riser.

2. In a liquid consumer system according to claim 1, a metering device inserted in said fuel conduit means between said fuel tank and said riser.

3. In a liquid consumer system according to claim 2, the cross section of passage of said thermal feed system being larger than that of said metering device.

4. In a liquid consumer system according to claim l, a metering device inserted in said fuel conduit means between said fuel tank and said riser, said metering device being arranged remote from said thermal feed system.

5. In a liquid consumer system according to claim l, a metering device inserted in said fuel conduit means between said fuel tank and said riser, said metering device being out of direct heat contact with said riser.

6. In a liquid consuming system, a consumer, a fuel tank at a higher level than said consumer, means to maintain a fuel level below a maximum in said tank, an outlet in the lower part of said fuel tank, fuel conduit means between said outlet to said consumer, a thermal feed system including a riser forming part of said fuel conduit means, said riser having an upper end at a level above said maximum fuel level in said tank, a portion of said fuel conduit means leading from said upper end downward to said consumer, means for heating at least a portion of said riser at a level lower than the lowest point of said outlet for lifting the fuel in said riser to at least said upper end by thermal action from where the fuel liows through said descending fuel conduit portion to said consumer, a metering device inserted in said fuel conduit means between said fuel tank and said riser, said metering device being arranged remote from said thermal feed system, the cross section of passage of said thermal feed system being larger than that of said metering device.

7. In a liquid consuming system, a consumena fuel tank at a higher level than said consumer, means to maintain a fuel level below a maximum in said tank, an outlet in the lower part of said fuel tank, fuel conduit means between said outlet to said consumer, a thermal feed system including a riser forming part of said fuel conduit means, said riser having an upper end at a level above said maximum fuel level in said tank, a portion of The . said fuel conduit means leading from said upper end downward to said consumer, means for heating at least a portion of said riser at a level lower than the lowest point of said outlet to such temperature that the fuel is at least partly evaporated, whereby the fuel is lifted in said riser by thermal action slightly above said upper 5 end from where the fuel ows through said descending fuel conduit portion to said consumer, a metering device inserted in said fuel conduit means between said fuel tank and said riser, said metering device being out of direct heat contact with said riser, the cross section of 10 passage of said thermal feed system being larger than that of said metering device.

References Cited in the file of this patent UNITED STATES PATENTS 

